Mix the dressing. In a large bowl, whisk together Greek yogurt, mayonnaise (if using), Dijon, lemon juice, honey, garlic, salt, and pepper until smooth and creamy. Adjust lemon and salt to taste.
Prep your mix-ins. Chop the celery, apple, and red onion into small, even pieces so every bite has a nice crunch.
Roughly chop the herbs and nuts.
Combine with chicken. Add the shredded chicken to the bowl with the dressing. Fold in the celery, apple, onion, nuts, and herbs until everything is evenly coated.
Taste and tweak. Add a pinch more salt, a squeeze of lemon, or an extra spoon of yogurt if you want it creamier. If you like sweetness, stir in a few grapes or dried cranberries.
Chill (optional but recommended). Cover and refrigerate for 20–30 minutes.
This helps the flavors meld and the texture set.
Serve your way. Spoon onto toasted whole-grain bread, tuck into a wrap, pile into lettuce cups, or serve over a big salad with cucumbers and tomatoes.